HOME These are services/company's I have used, but provided only for information, use at your own risk.
Texas State Board of Veterinary Medical Examiners
Vaccinateme.org
Cheapest Vaccinations!
Chisholm Ridge Pet Hospital
1100 North Blue Mound Rd. #160
Saginaw, TX
817-234-9919
Met the Dr.s (husband & wife) very sweet.  I have not used their services but have had clients rave about the experience.
LOCAL DOG PARK
www.fortwoof.org
Parkside Animal Hospital
1780 Rufe Snow Dr.
Keller, TX 76248
817-281-1111
Saw a tech I once worked with.  Prices are fair.  Appt. fair on wait time, Dr. was excellent.  Food costs were not competitive.
http://www.fortworthgov.org/
Look at the city calendar for dates and times for low cost clinic city registration & rabies vaccinations for (4$) , and microchips (10$ with proof of rabies). 
ABC Clinic
500 South Fwy
Fort Worth, TX
817-332-8787
I have not used them, but their prices are reasonable especially for spay and neutering.
Bedford Oaks Animal Clinic
Dr. Rowe
Bedford, TX
817-354-0655
Very reasonable costs.  Most regular visits are conducted by a nurse which justifies the low cost.  Competitive prices on vaccinations.  Downfall:  hard to obtain prescription.
Other Non Pet Services
Keller Feed Store
483 N. Main Street
Keller, TX 76248
817-431-2539
Offers some less expensive dog food, treats, other needs, as well as mobile vet stop for cheaper vaccinations.  Also, there are over the counter meds you can get for your pet.  But remember, some places do not accept these if you are having your pet stay (for ex: boarding, pet sitting, grooming, vets, and pet parks, be advised.)
VCA Saginaw
817 North Saginaw Blvd.
Saginaw, TX 76179
817-232-8193
I have not used the actual Veternarian, but some of my clients have.  Food costs are outstanding and customer service is great.